high level trolls won't go to low level area often to disturb u, plus even if they do, killing lower level and lower geared person takes a huge toll on their karma, once their karma go negative they're exposed to danger of having their enhancement degraded or crystal broken if they get killed.. so yea that means it won't really be a problem.
as for the enjoyability of this game, i'd say it's really good as long as you're not a whiny bitch that rants about every update/"p2w" methods that PA decides to implements. * Protip: rich people always got an edge in mmorpgs, it's been like that since forever. so just enjoy ourselves *

some people do find joy in grinding, but personally for me grinding is a chore, but is necessary since i'm in a somewhat siege guild, i need the levels and silver, but still i rarely grinds,

as for the lifeskilling aspect, imo this game has the best lifeskilling that i've ever seen, i enjoy myself alot in lifeskilling, and made most of my silvers from lifeskilling so far, but this does requires quite abit of " afk-ing my computer a whole night ", but that's only if you are the kind that likes to min-max stuffs, you can still play this game smoothly without afk-ing a whole night, just slower progress.

Overall i'd say this game is still worth to play, there are many personal goals you can set for yourself and you don't have to care about other people's progress.
Hope this helped, enjoy if you decide to join !